The present invention is particularly applicable but not necessarily limited to bearing alloys as well as composite bearing materials of the type suitable for fabricating bearing components for use in high performance reciprocating internal combustion engines. A typical heavy-duty aluminum bearing alloy of the type heretofore employed for such bearing materials is disclosed in U.S. Pat. No. 2,760,860, granted Aug. 28, 1956, for "Bearing Alloy", which is assigned to the same assignee as the present invention. In addition to the bearing alloy described in the aforementioned U.S. patent, various alternative aluminum alloys have heretofore been used or proposed for use in the fabrication of bearing components adapted for heavy-duty use, such as for use as connecting rods and main bearings of internal combustion engines, including diesel engines, as well as thrust washers, bushings and plain and flanged sleeve bearings in other sections of the engine and drive train components of vehicle drive systems.
The increasing severity of operating conditions to which bearings of the foregoing type are being subjected as a result of design innovations for increasing the performance and efficiency of internal combustion engines has in some situations occasioned a premature failure of prior art bearing alloys. Attempted modifications of such alloys to improve their physical strength properties and fatigue resistance, even including special heat treatments of the bearing component after forming operations, has heretofore been unsuccessful due to the detrimental effects of such alterations on other desirable and necessary properties including the bearings lining's resistance to corrosion, cavitation and wear, and its slipperiness, embeddability and conformability properties. Manufacturing considerations, including the capability of the alloy to be continuously cast and rolled into strip stock without incurring segregation and/or hot shortness and the ability to subsequently roll bond the bearing strip stock to a hard metal backing strip, are also necessary characteristics of a commercially acceptable bearing alloy.
The present invention overcomes the problems and disadvantages of prior art type aluminum bearing alloys by a controlled modification in the amounts and types of alloying constituents providing therewith a synergistic effect, whereby a substantial improvement in the fatigue resistance and tensile strength properties of the bearing alloy is achieved without any sacrifice in the other desirable and necessary characteristics of the bearing material and its capacity to be produced and fabricated into bearing components employing conventional mass-production manufacturing techniques without requiring any special heat treatments.